How old is glacier ice?

    • The age of the oldest glacier ice in Antarctica may approach 1,000,000 years old
    • The age of the oldest glacier ice in Greenland is more than 100,000 years old
    • The age of the oldest Alaskan glacier ice ever recovered (from a basin between Mt. Bona and Mt. Churchill) is about 30,000 years old.

    Glacier flow moves newly formed ice through the entire length of a typical Alaskan valley glacier in 100 years or less. Based on flow rates, it takes less than 400 years for ice to transit the entire 140 + mile length of Bering Glacier, Alaska’s largest and longest glacier.

    Learn more: USGS Water Science School - Glaciers: Things to Know 

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    Which mountain in the conterminous U.S. has the most glaciers?

    Mount Rainier, Washington, at 14,410 feet (4,393 meters), the highest peak in the Cascade Range, is a dormant volcano whose glacier ice cover exceeds that of any other mountain in the conterminous United States. Mount Rainier has approximately 26 glaciers. It contains more than five times the glacier area of all the other Cascade volcanoes...

    How long can we expect the present Interglacial period to last?

    No one knows for sure. In the Devils Hole, Nevada , paleoclimate record, the last four interglacials lasted over ~20,000 years with the warmest portion being a relatively stable period of 10,000 to 15,000 years duration. This is consistent with what is seen in the Vostok ice core from Antarctica and several records of sea level high stands. These...

    Are today's glaciers leftovers from the Pleistocene ice age?

    Yes and no. It depends on which glaciers you are considering. Parts of the Antarctic Continent have had continuous glacier cover for perhaps as long as 20 million years. Other areas, such as valley glaciers of the Antarctic Peninsula and glaciers of the Transantarctic Mountains may date from the early Pleistocene. For Greenland, ice cores and...

    How many glaciers currently exist in Alaska?

    Based on the most recent comprehensive survey in 2011, there were about 27,000 glaciers in Alaska. However, the number of glaciers is a misleading statistic. Scientists are more interested in total glacial land coverage as a measure. The number of glaciers is less important since large ones can split up into several as they retreat. The amount of...

    Was all of Alaska covered by glaciers during the Pleistocene Ice Age?

    No--most of interior Alaska, south of the Brooks Range and north of the Alaska Range, was a non-glaciated grassland refuge habitat for a number of plant and animal species during the maximum Pleistocene glaciation. This ice-free corridor also provided one route for humans to move into North America. Learn more: USGS Water Science School - Glaciers...

    Do ice worms exist?

    Yes, ice worms do, in fact, exist! They are small worms that live in glacial ice in Alaska, Washington, Oregon, and British Columbia; they have not been found in glaciers elsewhere. Contrary to stories and songs, they do not give glacier ice its blue color and they don't grow to lengths of 50 feet. (These myths were made popular by poet Robert...

    Is glacier ice a type of rock?

    Glacier ice, like limestone (for example), is a type of rock. Glacier ice is actually a mono-mineralic rock (a rock made of only one mineral, like limestone which is composed of the mineral calcite). The mineral ice is the crystalline form of water (H 2 O). Most glacier ice forms through the metamorphism of tens of thousands of individual...

    Why is glacier ice blue?

    Glacier ice is blue because the red (long wavelengths) part of white light is absorbed by ice and the blue (short wavelengths) light is transmitted and scattered. The longer the path light travels in ice, the more blue it appears. Learn more: USGS Water Science School - Glaciers: Things to Know

    Where are Earth’s glaciers located?

    Glaciers exist on every continent except Australia. Approximate distribution is: 91% in Antarctica 8% in Greenland Less than 0.5% in North America (about 0.1% in Alaska) 0.2% in Asia Less than 0.1% are in South America, Europe, Africa, New Zealand, and Indonesia.

    What is a glacier?

    A glacier is a large, perennial accumulation of crystalline ice, snow, rock, sediment, and often liquid water that originates on land and moves down slope under the influence of its own weight and gravity. Typically, glaciers exist and may even form in areas where: mean annual temperatures are close to the freezing point winter precipitation...
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    Date published: May 10, 2017

    Glaciers Rapidly Shrinking and Disappearing: 50 Years of Glacier Change in Montana

    The warming climate has dramatically reduced the size of 39 glaciers in Montana since 1966, some by as much as 85 percent, according to data released by the U.S. Geological Survey and Portland State University.

    Date published: September 28, 2016

    Fifty Years of Glacier Change Research in Alaska

    ANCHORAGE, Alaska — This year marks the 50th anniversary of one of the longest continuous glacier research efforts in North America.

    Date published: March 18, 2015

    From Icefield to Ocean - What Glacier Change Might Mean for the Future of Alaska

    Frozen bodies of ice cover nearly 10 percent of the state of Alaska, but the influence of glaciers on the environment, tourism, fisheries, hydropower, and other important Alaska resources is rarely discussed.

    Date published: January 20, 2015

    Melting Glaciers Increase the Flow of Carbon to Downstream Ecosystems

    ANCHORAGE, Alaska Melting glaciers are not just impacting sea level, they are also affecting the flow of organic carbon to the world’s oceans, according to new research that provides the first ever global-scale estimates for the storage and release of organic carbon from glaciers.

    Date published: August 25, 2010

    Washington’s Benchmark Glacier Still Shrinking

    TACOMA, Wash. — Washington’s only “benchmark” glacier continues to lose mass as a result of changes in climate, according to a report by the U.S. Geological Survey.

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    July 19, 2018

    Drilling an Ice Core

    Researchers start drilling an ice core in the Greater Yellowstone Ecosystem.

    July 27, 2017

    USGS Public Lecture: Warm Ice—Dynamics of Rapidly Changing Glaciers

    • Glacier Numerology – The how big, how long, how thick, how much, how often, of glacier science.
    • Glacier Photography – While a picture may be worth a thousand words, a collection of images may tell a complete forensic story.
    • Glacier Geophysics – How new technologies are being introduced to reexamine and refine decades old glacier analyses.
    microstructures of an ice core
    April 13, 2017

    Microstructures of an ice core

    Characterization of the microstructures of an ice core reveals the mechanisms by which large bodies of ice deform and flow.

    Crevices on glacier, Juneau Icefield
    December 31, 2016

    Crevices on glacier, Juneau Icefield

    Crevices on glacier, Juneau Icefield

    Jackson Glacier in Glacier National Park, circa 1911.  Image 8 of 8.
    August 9, 2016

    Jackson Glacier in Glacier National Park, circa 1911. Image 8 of 8.

    Jackson Glacier in Glacier National Park, circa 1911.  Image 8 of 8.

    This is a glacier animation for Glacier National Park.
    April 5, 2016

    Glacier Animation

    The simulation below reflects the predicted exponential rise in atmospheric CO2 concentrations, a 2xCO2 "global warming" scenario, with a concurrent warming of 2-3 degrees centigrade (4-5 degrees Fahrenheit) by the year 2050. In addition it assumes that precipitation, primarily in the form of rain, will increase over the same time period about 10 percent (based on the

    Mapping the glacier's edge in Glacier National Park.
    April 5, 2016

    Mapping the glacier's edge in Glacier National Park.

    Mapping the glacier's edge in Glacier National Park.

    Image: Layered Ice
    January 21, 2014

    Layered Ice

    An ice jam on the East Branch Wesserunsett Stream in Athens, Maine in January 2014 left 3-5 ft ice walls on the riverbanks. On a January 21, 2014 site visit Nick Stasulis and Charlie Culbertson chisled away some of the ice wall so a discharge measurement could be made. The ice walls showed the multiple layers of river ice, snow and slush that froze in over the winter.

    Attribution: Water Resources
    Louis Sass standing in a hole dug in the snow holding a coring tube.
    February 29, 2012

    Louis Sass with an ice core in a snow pit

    Louis Sass with an ice core in a snow pit

    Image: Surprise Glacier
    August 22, 2008

    Surprise Glacier

    Surprise Glacier, Harriman Fiord, western Prince William Sound.

    February 28, 2008

    PubTalk 2/2008 — Alaska's Rivers of Ice

    USGS scientist Bruce Molnia, discusses the impact of changing climate and conditions on Earth's glaciers

    By Bruce Molnia, Geologist

    See excerpts from this full-length film feature showing:

    • How and where glaciers form
    • How scientists study glaciers and climate
    • The processes of glacial erosion and
    December 8, 2005

    PubTalk 12/2005 — Frozen in Time

    How Ice Cores Are Revealing the Composition and Temperature of Earth's Atmosphere During the Past Million Years

    by Todd Hinkley, Geologist


    • Scientifically invaluable ice cores taken from Antarctic and Arctic ice are stored and safe guarded at the U.S. National Ice Core Laboratory, operated by the U.S. Geological Su rvey